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AMO Physics with Intense XUV and X-ray Free Electron Lasers John T Costello National Centre for Plasma Science & Technology (NCPST)/ School of Physical Sciences, Dublin City University h#p://www.ncpst . ie h#p://www.physics.dcu.ie/

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John T Costello

National Centre for Plasma Science & Technology (NCPST)/ School of Physical Sciences, Dublin City University ¡ h#p://www.physics.dcu.ie/ ~jtc ¡ h#p://www.ncpst.ie ¡

AMO Physics with Intense XUV and X-ray Free Electron Lasers

AICQT, Maynooth 1 June 2016

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Laser Plasma/AMO Physics @ NCPST - 6 laboratory areas focussed on pulsed laser matter interactions (spectroscopy/ imaging / particle detection)

DCU Laser Plasma-AMO Physics Group

AICQT, Maynooth 1 June 2016

Principal Investigators (6): John T. Costello, Eugene T. Kennedy (Emeritus), Lampros Nikolopoulos (T), Jean-Paul Mosnier & Paddy Hayden (SFI SIRG PI) Current Postdocs (2): Dr. Pramod Pandey & Dr. Mossy Kelly Current PhD students (9): Nichola Walsh, Ben Delaney, Stephen Davitt, Hu Lu, Getasew Wubetu, William Hanks, Muhammed Alli, Sadaf Syedah & Lazaros Varvarezos Recent Int’l Interns (2012-16): K Nishant/R Tejaswi, (LNMIIT, Jaipur), C Hand, (NUIM), S Reddy/R Namboodiri/A Neettiyath (IIT Madras), R Singh/S Gupta (IIT Kanpur), S Howard (Notre Dame), I-M Carrasco Garcia (Malaga), R. Black (Notre Dame), P Colley (Notre Dame) Recent PhD Grads (2009-2016): Padraig Hough, Conor McLoughlin, Rick O’Haire, Vincent Richardson, Dave Smith, Tommy Walsh, Jack Connolly, Jiang Xi, Leanne Doughty, Eanna MacCarthy, Colm Fallon, Mossy Kelly, D Middleton, Cathal O’Broin, Brian Sheehy & Saikumar Inguva Recent Past Postdocs (2012-2015): Satheesh Krishnamurthy (Open Univ. UK), Pat Yeates (Elekta Oncology UK) & Subhash Singh (U. Allahabad), Colm Fallon (IC4 – DCUBS).

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Collaboration @ FLASH-DESY & FERMI- ELETTRA

XFEL: P. Radcliffe & M. Meyer Paris (UPMC): R. Taieb (T) & A. Maquet (T) FERMI: P. O’Keefe, L. Avaldi & K. Prince DESY (Hamburg): K. Tiedke, S. Düsterer, W. Li, A. Sorokin & P. Juranić,J. Feldhaus Orsay: D. Cubaynes Queen’s University Belfast: C. L. S. Lewis Moscow State University : A. N. Grum-Grzhimailo, E. V. Gryzlova, S. I. Strakhova Crete: P. Lambropoulos (T) Oulu/GSI: S. Fritzsche (T) DCU: T. J. Kelly, N. Walsh, E. T. Kennedy, L Nikolopoulos & J. T. Costello

AICQT, Maynooth 1 June 2016

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Collaboration @ LCLS X-ray FEL (SLAC)

DESY (CFEL): I. Grguras, M Hoffmann & A. Cavalieri DESY (FLASH): S. Düsterer & J. Feldhaus DCU: T. J. Kelly, E. Kennedy, V. Richardson, L. Nikolopoulos (T) & J. T. Costello MPQ/TU-Munich: A. Maier, W. Helml, W. Schweinberger & R. Kienberger Ohio (OSU): C. Roedig, G. Doumy* & L. DiMauro Tohuku University: K. Ueda Hiroshima University: S. Wada SLAC: R. Coffee, J. Hastings, C Boestedt, J. Bozek et al. XFEL Gmbh: P. Radcliffe, T. Tschenscher & M. Meyer Moscow State University: N. Kabachnik

Thanks to Paul Emma et al.

AICQT, Maynooth 1 June 2016

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Some members of the LCLS collaboration

AICQT, Maynooth 1 June 2016

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1 minute

10 fs light pulse

10

  • 14 10
  • 9 10
  • 4 10

1

10

6

10

11 10 16 Age of universe

Time (seconds)

Computer clock cycle Camera flash Age of pyramid s One month

Human existence

as ps fs zs 10-18 s 10-15 s 10-12 s 10-21 s

TIMESCALES - HOW FAST IS FAST ?

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X-ray – How X-ray is X-ray ? Spectral Range: IR to the X-ray

Graphic: Courtesy, Prof. David Attwood (Berkeley)

AICQT, Maynooth 1 June 2016

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What do we want in an X-ray laser ?

The Holy Grail is an X-ray laser with variable pulse duration on the femtosecond to attosecond timescales with tunable wavelength, variable polarisation and high energy per pulse (few 100 µJ to few 10 mJ)…..

AICQT, Maynooth 1 June 2016

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X-ray Free Electron Lasers (FEL) Main Components of an X-ray FEL

AICQT, Maynooth 1 June 2016

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vt

(c-v)t NuλU = vt λL = λu(1+K2/2)/2γ2 1GeV machine γ ~ 2000 λu ~ 2.7 cm / λlaser ~ 6nm Nu λL = (c-v)t ⇒ λL ~ λU (c-v)/v ~ λu/2γ2 γ = E/mc2 Electron bunch slips behind the lightwave by λ per undulator period λU K = eBλu/2πmc Wavelength tunable – by electron beam energy or by tuning the undulator gap λph

SASE-FEL, Fundamental Principle

AICQT, Maynooth 1 June 2016

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SLIDE 11

300 m

FLASH Overview

  • LINAC Energy : ~ 1 GeV

~ 4 – 60 nm

Laser Bunch Compressor Bypass Undulators Collimator Bunch Compresso r 5 MeV 127 MeV 450 MeV 1000 MeV Accelerating Structures Diagnostics FEL Diagnostics RF-gun

X-ray Free Electron Lasers (FEL)

FLASH - Operation & Physical Layout

AICQT, Maynooth 1 June 2016

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X-ray Free Electron Lasers (FEL)

lcls.slac.stanford.edu

LCLS Overview and Specifications

AICQT, Maynooth 1 June 2016

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X-ray Free Electron Lasers (FEL)

XFEL – Under Construction…… 2017

AICQT, Maynooth 1 June 2016

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X-ray Free Electron Lasers (FEL)

XFEL – Under Construction…… 2017

AICQT, Maynooth 1 June 2016

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  • High flux per pulse – typ. 1013 photons/pulse
  • Tunable pulsewidth – from 1 to few 100 fs
  • Ergo high peak intensity – up to few 1020 W.cm-2

possible

  • Seeded and unseeded modes now possible
  • Unseeded bandwidth – 0.2 – 1.0%
  • Seeded bandwidth – 0.005% (typ.) / λ/Δλ

Δλ ≥ 104

  • Synchronisation to optical fs lasers relatively easy
  • EUV/EUV and X-ray/X-ray pump-probe possible

USPs of XUV & X-ray FELs (XFELs)?

AICQT, Maynooth 1 June 2016

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So the Holy Grail is now largely realised as the SASE EUV and X-ray FELs at SLAC-Stanford, SCSS & SACLA-RIKEN, FLASH-DESY (+future European XFEL), FERMI@ELETTRA- Trieste, SwissFEL-PSI, Pohang, Shanghai, Dalian, etc……..

Very recently [2012] seeding of LCLS, SCSS and FERMI have resulted in

Technology Now…..

AICQT, Maynooth 1 June 2016

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Ionization in Intense Fields

  • 1. Rudiments of ionization processes in intense laser

fields

  • 2. Photoionization experimental setups (FLASH & DESY)
  • 3. One colour – two photon ionization
  • 4. Two colour Ionization – physics and characterisation
  • 5. Some conclusions

AICQT, Maynooth 1 June 2016

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e-

a) Single Photon Ionization (SPI)

IP

The Atomic Photoelectric Effect

KE(e-) = hνEUV - IP

b) Multi Photon Ionization (MPI)

IP

KE(e-) = nhνNIR - IP (EUV Synchrotron) (NIR Laser)

AICQT, Maynooth 1 June 2016

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Intensity/ Wavelength Photon Energy

What happens as the laser intensity (field strength) grows ?

AICQT, Maynooth 1 June 2016

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How can you determine in which regime the interaction resides ?

*L V Keldysh, Sov.Phys-JETP 20 1307 (1965)

γ = IP 2Up

UP = 9.3×10−14I Wcm−2

( ) λ

2 µm

( )

eV

Keldysh Parameter

IP = Ionization Potential Up = Ponderomotive Pot.

AICQT, Maynooth 1 June 2016

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So for EUV lasers, multi-photon ionization is the primary processs and will involve few photons and potentially few electrons

For Ti-sapphire laser: 800 nm, 1015 Wcm-2, γ ~0.45 (TI/FI regime Example: Helium in intense laser fields For an EUV laser: 8 nm, 1015 Wcm-2, γ ~45 (MPI regime)

Keldysh - Ionization Regime

Multiphoton Ionization Tunnel Ionization Field Ionization γ>>1 γ ~ 2 γ <<1

AICQT, Maynooth 1 June 2016

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  • Ultra-dilute targets
  • Photo-processes with ultralow cross-sections
  • Pump and probe experiments (EUV + EUV or EUV +

Opt.)

  • Single shot measurements
  • Few-photon single and multiple ionization

processes NB1: Makes inner-shell electrons key actors in non- linear processes for the first time NB2: Re-asserts primacy of the photon over field

USPs of XUV & XFELs in AMO Physics ?

AICQT, Maynooth 1 June 2016

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Experimental Setups (DESY & SLAC)

  • 1. Rudiments of ionization processes in intense laser

fields

  • 2. Photoionization experimental setups (FLASH &

LCLS)

  • 3. One colour – two photon ionization
  • 4. Two colour Ionization
  • 5. Some conclusions

AICQT, Maynooth 1 June 2016

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Two colour ATI/ Laser Assisted PES

Experimental Layout at FLASH - (EU-RTD)

Photoelectron Spectroscopy @ FLASH

AICQT, Maynooth 1 June 2016

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Rendered Image:

High Field Chamber (AR-ETOF) and Diagnostics (MBES) Chamber

AMO PES Chamber at LCLS

http://lcls.slac.stanford.edu

Focussing Optics K-B Mirrors

AICQT, Maynooth 1 June 2016

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Two Photon Ionization (TPI) of Xe and Kr atoms in an Intense Field

  • 1. Rudiments of ionization processes in intense laser

fields

  • 2. Photoionization experimental setups (FLASH & DESY)
  • 3. One colour - two photon ionization
  • 4. Two colour Ionization
  • 5. Some conclusions

AICQT, Maynooth 1 June 2016

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Non-linear processes in the EUV & X-ray

  • Question. What is the simplest experiment you can carry
  • ut in non-linear optics ? Answer. Either two-photon

absorption (TPA) or second harmonic generation (SHG) …….. 1 3 2

694 nm 694 nm 420 nm

AICQT, Maynooth 1 June 2016

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Motivation - Xe TPI in intense EUV fields

Sorokin, Richter et al., PTB, PRL 2007 – Ion Spectroscopy !!

AICQT, Maynooth 1 June 2016

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Xe + hν (93 eV) - Xe+(4d-1) + e- (~25 eV)

FEL only. hν ~ 93 eV Xe + hν → Xen+ + e-

Replace Ion TOF by MBES – photoelectron spectroscopy Intensity scaling... Weakest field…

AICQT, Maynooth 1 June 2016

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Xe + 2hν (93 eV) - Xe+(4d-1) + e- (~ 118 eV)

  • Using MBES, first evidence of two

photon inner shell ionisation, (in this case) of 4d electron –

Xe + 2hv → Xe+ 4d9 + e-

  • ‘Retardation field’ applied to suppress

low KE electrons (one photon processes) – hence electrons detected are due solely to multiphoton events

  • Energetically –

2 × (93) eV – 118 eV = 68 eV

  • Yield scales quadratically, n=1.95 ± .2

Now ramp up the intensity to > 1015 W.cm-2………….

Phys Rev Lett 105 013001 (2010) ¡

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  • Xenon – Demonstration of an ‘above threshold absorption-ionization’

two-photon process involving an inner shell electron.

  • It is clear that the although single photon ionization processes

dominate, they are sufficiently important at high irradiance that, for a given intensity, much higher ionization stages can be reached compared to optical lasers.

  • The strength and the nature of the 4d → εf resonance may open up,

at high irradiance, additional ionization channels, namely the simultaneous multiphoton / multi-electron from the inner 4d shell, ‘inside-out ionization’ or ‘peeling the onion from the inside out’

  • Kr (Not Shown) – was the first step on the road to resonant NL

processes with EUV/X-rays…. REMPI at X-rays.

Xe - Richardson et al. PRL (July 2 – 2010), Kr - Meyer et al., PRL (May 28 - 2010)

Summary - One Colour

AICQT, Maynooth 1 June 2016

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XUV (X-ray) + IR Ionization

  • 1. Rudiments of ionization processes in intense laser

fields

  • 2. Photoionization experimental setups (FLASH & DESY)
  • 3. One colour – two photon ionization
  • 4. Two colour Ionization
  • 5. Some conclusions

AICQT, Maynooth 1 June 2016

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SLIDE 33

Atoms in Intense Superposed X-ray + IR Laser Fields Main objective

Study the effect of X-ray pulse width on fundamental photoionization processes in intense and ultrashort ionizing (X-ray) and dressing (Optical / IR) laser fields Two Extremes:

X-ray pulse duration comprises ‘many’ optical cycles X-ray pulse duration is less than ½ optical cycle

Intermediate State:

AICQT, Maynooth 1 June 2016

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SLIDE 34

E.S. Toma et al. PRA 62 061801 (2000)

Two colour ATI/ Laser Assisted PES

Electron Spectrometer Gas Jet NIR (800 nm) fs laser pulse XUV/X-ray Superposition of visible and XUV pulses in a noble gas jet hωir =1.55eV Ar(IP) 15.76 eV Sideband intensity very sensitive to XUV-IR pulse area

  • verlap. - Cross

Correlation… Schins et al. PRL 73, 2180 (1994)

AICQT, Maynooth 1 June 2016

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SLIDE 35

E.S. Toma et al. PRA 62 061801 (2000)

Two colour ATI/ Laser Assisted PES

Electron Spectrometer Gas Jet NIR (800 nm) fs laser pulse XUV/X-ray Superposition of visible and XUV pulses in a noble gas jet hωir =1.55eV Ar(IP) 15.76 eV Sideband intensity very sensitive to XUV-IR pulse area

  • verlap. - Cross

Correlation… Schins et al. PRL 73, 2180 (1994)

AICQT, Maynooth 1 June 2016

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SLIDE 36

Atoms in ‘Long’ XUV (X-ray) + IR Fields

NIMA 83, 516-525 (2007)

  • Appl. Phys. Lett 90 131108 (2007)

Sideband number/intensity depend strongly on XUV/NIR overlap ⇒ by comparison with theory we are able to determine relative time delay to better than 100 fs 550 fs

  • 1. Ultrafast XUV-modulated optical-reflectivity methods
  • 2. ‘TEO’
  • C. Gahl et al., Nature Photonics 2 165-169 (2008)
  • A. Azima et al.,

APL,

  • T. Maltezopoulos et al., New J Phys 10 Art. No. 033026 (2008)

94 144102 (2009)

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SLIDE 37

Single Shot Atomic Streak Camera – SSASC => few fs pulse widths. Target: Neon, LCLS: >870 eV, ~1 - 4 fs, Laser: OPA (2000 nm, ~ 7 fs),

  • a. Without dressing field =>

unshifted, no broadening…..

  • b. With dressing field (zero crossing)

=> unshifted, broadened…..

  • c. With dressing field (peak value)

=> shifted, not broadened…..

Atoms in ‘Short’ XUV (X-ray) + IR Fields

* R. Kienberger et al., J. Mod. Opt 52 261-275 (2005) AICQT, Maynooth 1 June 2016

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SLIDE 38

Experimental Layout at LCLS

Two colour ATI/ Laser Assisted PES

Measurement of few fs pulses @ LCLS

! Nature Photonics 8 pp950 - 957 (2014)

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SLIDE 39

Measurement of few fs pulses @ LCLS

LCLS low current/ slotted spoiler/ few fs mode - Data still under analysis……

  • Process. Ne + hν (1.8 keV) -> Ne+ (1s-1) + e- +IL (1014

W.cm-2)

Essentially mapping time (fs) to energy in (eV) allows one to measure X- ray (and EUV) pulse widths to attosecond accuracy provided the X-ray (EUV) pulse width is less than one one half cycle of the optical laser in duration !!

3fs case - simulation and experiment………

AICQT, Maynooth 1 June 2016

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SLIDE 40

Sub-femtosecond pulses @ LCLS

800 as X-ray pulse !!

  • Process. Ne + hν (1.8 keV) -> Ne+ (1s-1) + e- +IL (1014

W.cm-2) 200 uJ in 800 as = 2 x 10-4 J/ 8 x 10-16 s = 0.25 TW peak power Focused to a spot of 10 um = 10-6 cm2 => An irradiance of: 2.5 x 1017 W.cm-2 !!!

AICQT, Maynooth 1 June 2016

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SLIDE 41

Generate single (picosecond) cycle pulse using optical rectification

  • f Ti-Sappire laser pulses – field ~ 50MV/m maximum

41

Single Cycle THz Streaking @ FLASH 41

Schematic layout of the THz Streaking Experiment at FLASH

Nature Photonics 6 pp852-857 (2012)

Femtosecond Atomic Streak Camera

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SLIDE 42

Generate single (picosecond) cycle pulse using optical rectification of Ti-Sappire laser pulses – field ~ 50MV/m maximum

42

Single Cycle THz Streaking @ FLASH

42 Principle of the experiment

Attosecond Photoelectron Streaking showing how the E-field of a few cycle fs laser pulse can be mapped – MPI-Q.

Femtosecond Atomic Streak Camera

AICQT, Maynooth 1 June 2016

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SLIDE 43

43

Single Cycle THz Streaking @ FLASH 43

A Cavalieri et al. from CFEL, DCU, XFEL & DESY Single cycle THz Photoelectron Streaking showing how the E-field of a single cycle ps laser pulse can be mapped

Nature Photonics 6 pp852-857 (2012)

Jitter measurements on 50 consecutive streak traces

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SLIDE 44

44

LCLS - Single Cycle THz Streaking

44

A Cavalieri et al. from CFEL, DCU, XFEL & SLAC

If the dispersed bunch is intercepted by a ‘V-shaped’ vertical slot, then the emittance of the all but TWO small parts in space (time) of the bunch is ‘spoiled’ -=> 2 X ‘few fs’ pulses of variable separation result. P Emma et al., PRL 109 254802 (2012)

AICQT, Maynooth 1 June 2016

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SLIDE 45

Based on theoretical work by: Nikolay Kabachnik et al., Moscow State Univ.

A.K. Kazansky, N.M. Kabachnik, JPB 42, 121002 (2009) A.K. Kazansky, N.M. Kabachnik, JPB 43, 035601 (2010) Core hole lifetime τ (Ne 1s) = 2.4fs NIR: 800 nm, 1 x 1012 W/cm2 LCLS: 1 keV, 2-5 fs Optical cylce T (800nm) = 2.6fs Simulated spectrum for electron emission in the direction of the field (0°) Angle Resolved Sideband Spectra Auger lifetime similar to optical (800 nm) cycle

But what about the intermediate (few

  • ptical cycle) regime ?

AICQT, Maynooth 1 June 2016

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SLIDE 46

High Field Chamber (AR-eTOF)

  • AMO Chamber and Specifications

lcls.slac.stanford.edu

θ φ comment 1 0º 90º Along y-axis 2 35.3º 90º Magic angle in xy dipole plane 3 90º 90º Along x-axis 4 54.7º 0º Non-dipole 5 90º 35.3º Non-dipole

  • 1. Based on a successful design used

by the Denis Lindle (RIP) group at ALS – designed for up to 5keV electrons

  • 2. Transmission flat for Ekin> 20 eV
  • 3. E/ΔE up to 5,000

AICQT, Maynooth 1 June 2016

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SLIDE 47

47

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!(

./.01234-564.160-.4.278-9.:; 641.4<618-9=2>+-?461<;

  • @A-B3/+-C-#D-EFGH)-C-#D-II-EFGH)-43-/=<.2-,#+&

!"# !$# "## "%# "&# "'# # % & ' ( ) * ! +,%#

!'

  • .-/0123,453-05/,-3-167,8-9:

530-3;507,8<1=>,?350;:

, , @A,B2.>,C,#D,EFGH(,C,#D,II,EFGH(,32,.<;-1,+#>%

LCLS: 1 keV, “4fs”, 20pC bunch current NIR : 800nm, 1 mJ, 3ps

Strong sideband structure Strong angular effect 90° 54.7° 0°

1 x 1012 W/cm2 6 x 1011 W/cm2

laser off laser on

SB modulation – few/sub-optical cycle effects

0°

  • Phys. Rev. Lett 108

063007 (2012)

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SLIDE 48

48

SB modulation – few/sub-optical cycle effects

48

Theory – accounting for spatial variation of the laser field

theory theory

  • Phys. Rev. Lett 108

063007 (2012)

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SLIDE 49

49

NEW !! All Optical Synchronisation - FLASH

49 A Cavalieri et al. from CFEL, DCU, MPI (SDM), SLAC & XFEL

Nature Comms 6

  • Art. No. 5938 (2015)
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SLIDE 50

Measuring Polarisation of XFELs

T Mazza et al. (XFEL GmbH, DESY, FERMI@ELECTTRA, DCU, MSU, etc)

Theory - Kazansky, A. K., Grigorieva, A. V. and Kabachnik, N. M. Circular Dichroism in Laser-Assisted Short Pulse Photoionization. Phys. Rev. Lett. 107, 253002 (2011). DDCS (Expt./Th.) CD (L-R/L+R.) DDCS (Expt./Th.)

Nature Comms 5

  • Art. No. 3628 (2014)
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SLIDE 51

Next Steps

  • 1. Rudiments of ionization processes in intense laser

fields

  • 2. Photoionization experimental setups (FLASH & DESY)
  • 3. One colour – two photon ionization
  • 4. Two colour Ionization
  • 5. Some conclusions

AICQT, Maynooth 1 June 2016

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SLIDE 52

X-Ray Lasers - Future Self - Seeded FELs, e.g., LCLS…..

Lutman et al., PRL 113 Art. No. 254801 (2014)/Amann et al. Nature Photonics 6, 693 (2012)

Single-Shot Spectra Multi-Shot Averaged Spectra

AICQT, Maynooth 1 June 2016

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SLIDE 53

X-Ray Lasers - Future In Conclusion

  • 1. To date we have looked only at one and two colour non-resonant

photoionization processes

  • 2. Now – FELs seeded and easily tunable - we can explore

resonant processes where inner shell electrons dominate Next steps (XFEL Technology): X-CPA XFELs are finally becoming real lasers – truly monochromatic, fully phase coherent, collimated…... If it can be done with an optical laser – we can now propose it for XFELs….

AICQT, Maynooth 1 June 2016

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SLIDE 54

Regular Articles

  • 1. Spectroscopic characterization of vacuum ultraviolet free electron laser pulses, Optics Letters 31 1750 (2006)
  • 2. Two-color photoionization in xuv free-electron and visible laser fields, Phys. Rev. A 74, Rapid Communications, Art. no.

011401 (2006)

  • 3. Single-shot characterization of independent femtosecond extreme ultraviolet free electron and infrared laser pulses,
  • Appl. Phys. Lett 90, Art. no. 131108 (2007)
  • 4. Operation of the Free Electron Laser FLASH in the water window, Nature Photonics 1 336 (2007)
  • 5. An experiment for two-color photoionization using high intensity extreme-UV free electron and near-IR laser pulses,
  • Nucl. Inst. Methods in Res. A 583 pp516-525 (2007)
  • 6. Polarization control in atomic 2-color above threshold ionization, Phys. Rev. Letts 101 Art. no. 193002 (2008)
  • 7. Time-resolved pump-probe experiments beyond the jitter limitations at FLASH, Appl. Phys. Letts 94 Art. no. 144102

(2009)

  • 8. Two-Photon Excitation and Relaxation of the 3d-4d Resonance in Atomic Kr, Phys. Rev. Letts 104 Art. no. 213001

(2010)

  • 9. Two-photon inner-shell ionization in the extreme-ultraviolet (XUV), Phys. Rev. Letts 105 Art. no. 013001 (2010)
  • 10. Two-color experiments in the gas phase at FLASH, J. Electron. Spec. Relat. Phenom. 181 pp111-115 (2010)
  • 11. Femtosecond x-ray pulse length characterization at the LCLS FEL, New J. Phys. 13 Art. no. 093024 (2011)
  • 12. Theory of ac-Stark splitting in core-resonant Auger decay in strong x-ray fields, Phys. Rev. A 84 Art. no. 063419 (2011)
  • 13. Angle-resolved electron spectroscopy of laser-assisted Auger decay induced by a few-fs x-ray pulse, Phys. Rev. Letts.

108 Art. no. 063007 (2012)

  • 14. Atomic photoionization in combined intense XUV free-electron and infrared laser fields, New J. Phys. 14 043008

(2012)

  • 15. Dichroism in the above-threshold two-colour photoionization of singly charged neon, J. Phys. B: At. Mol. Opt. Phys. 45

085601 (2012)

  • 16. Controlling core hole relaxation dynamics via intense optical fields, J. Phys. B: At. Mol. Opt. Phys. 45 141001 (2012)
  • 17. Ultrafast X-ray pulse temporal characterization for free-electron lasers, Nature Photonics 6 852-857 (2012)
  • 18. Determining the polarization state of an XUV free-electron laser beam using atomic circular dichroism, Nature

Communications 5, 3628 (2014)

AICQT, Maynooth 1 June 2016

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SLIDE 55

Review Articles

  • 1. Photoionization experiments with the ultrafast XUV laser FLASH
  • J. T. Costello, J. Phys. Conf. Series 88 Art No. 012057 (2007)
  • 2. Experiments at FLASH
  • C. Bostedt, H. N. Chapman, J. T. Costello, J. R. Crespo Lopez-Urrutia, S.

Duesterer, S. W. Epp, J. Feldhaus, A. Foehlisch, M. Meyer, T. Mšller, R. Moshammer, M. Richter, K. Sokolowski-Tinten, A. Sorokin, K. Tiedtke, J. Ullrich and W. Wurth, Nucl. Inst. Meth. in Res. A 601 108-122 (2009)

  • 3. Non-linear processes in the interaction of atoms and molecules with

intense EUV and X-ray fields from SASE free electron lasers (FELs)

  • N. Berrah, J. Bozek, J. T. Costello, S. Duesterer, L. Fang, J. Feldhaus, H.

Fukuzawa, M. Hoener, Y. H. Jiang, P. Johnsson, E. T. Kennedy, M. Meyer,

  • R. Moshammer, P. Radcliffe, M. Richter, A. Rouzee, A. Rudenko, A.

Sorokin, K. Tiedtke, K. Ueda, J. Ullrich and M. J. J. Vrakking, Journal of Modern Optics 57 1015-1040 (2010)

  • 4. Two-colour experiments in the gas phase
  • M. Meyer , J. T. Costello , S. Düsterer , W. B. Li and P. Radcliffe
  • J. Phys. B: At. Mol. Opt. Phys. 43 Art No. 194006 (2010)
  • 5. Two-Color Experiments in the Gas Phase at FLASH

M Meyer et al., J Electron. Spec. Relat. Phenom 181, 111-115 (2010)

AICQT, Maynooth 1 June 2016

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Funding

Higher Education Authority – Programme for Research in Third Level Institutes (IV and V) Science Foundation Ireland – Investigator Programme – 12/IA/1742 & 07/IN.1/I1771 Irish Research Council (PhD Scholarships / Postdoctoral Fellowships) EU FP7 Erasmus Mundus Joint Doctorate ‘EXTATIC’ - FPA 0033-2012 and Marie Sklowdowska Curie – Proj. No. 628789

AICQT, Maynooth 1 June 2016